Vietnam and the killing fields

Earlier this week President Bush brought back the hoary argument that pulling out of Vietnam led to the killing fields of Cambodia and all the other terrible things -- boat people, reeducation camps, hundreds of thousands of deaths -- that came after the U.S. left the war and then stopped funding the failing South Vietnamese government. I'm working on a piece regarding some aspects of this argument, and here's a piece by author Gareth Porter that addresses the Cambodia killing fields aspect. He argues that when Nixon took office the Cambodian communist movement was weak and unlikely to overthrow Sihanouk. But a number of things Nixon did, including bombing Cambodia and secretly invading in Cambodia, strengthened opposition to Sihanouk and made the takeover by Pol Pot, which led to the killing fields and massive population relocation, more likely. It's a powerful argument and, I think, a correct one.